For physics • For physicists • For all

Working in physics: Have PhD, will travel

Life as a postdoctoral researcher offers opportunities for making independent contributions to science, but there are pitfalls too, as Margaret Harris explains.

What do you call someone with more skills than an apprentice but not enough to be a master? Europe’s medieval guilds recognized such people as journeymen, skilled workers paid by the day (in French, journée) who travelled between masters, gaining the experience needed to set up their own workshops. Modern academia uses another name — postdoctoral researchers.

Despite important differences between postdocs and their medieval predecessors (regular pay, for starters), the basic rationale for seeking a postdoc position has not changed. Newly minted PhD graduates may be well on their way to becoming experts in their fields, but most will have little experience in planning new research projects or managing students. A stint as a postdoc can fill this experience gap. By working with an established mentor for a short period of time (typically 1–3 years), new researchers gain not only subject-specific training but also help with “soft skills” like preparing grant applications and giving presentations — just what fledgling physicists need to develop into independent researchers. The results can be impressive: a 1999 survey by Science found that 43% of articles published in the journal that year had postdocs as the first named authors.

One reason for this prominence is that the expertise postdocs bring to their new research group often allows them to tackle existing problems in a new way. Another is the greater independence postdocs enjoy relative to PhD students. Although both work under the direction of a more senior scientist, postdocs are far more likely to set their own research agendas within a defined project — especially when the permanent faculty member is busy, senior or fond of attending conferences.

Recipients of funded postdoctoral fellowships — such as the research fellowships available in the UK from the Engineering and Physical Science Research Council (EPSRC) or the Royal Society — enjoy even greater autonomy. These awards provide an independent source of research money, allowing fellows to run their own mini-groups of PhD students and a postdoc or two. Above all, a postdoc position allows new researchers to focus on the science, without needing — as established academics do — to juggle teaching and administrative responsibilities.

What to look forThe most important thing to consider when evaluating a postdoc position is the research topic. “A physicist undertaking a postdoc should understand why they’re there, because the expectation is that they get off to a quick start,” says Mildred Dresselhaus, a nanophysicist at the Massachusetts Institute of Technology in the US and past president of the American Physical Society. The topic is also important because researchers are more likely to pursue careers related to their postdocs, rather than their PhD subjects, she believes. “[Postdocs] hone in on what they’re best at and what interests them the most,” she says.

Less obvious factors can also influence the outcome of a postdoc. A 2005 survey of US-based science postdocs by the research society Sigma Xi found positive correlations between postdoc satisfaction and the levels of training and structure universities provide. Postdocs in programmes that were structured also rated their faculty advisors more highly, reported fewer conflicts, and, intriguingly, published more papers per year than their counterparts in more informal environments.

Levels of training and structure vary between universities, although efforts are under way to improve this situation. In June 2008 a consortium of UK universities and funding bodies adopted a set of principles, the The Concordat to Support the Career Development of Researchers, aimed at promoting good practice in training early-career scientists. A similar initiative, the European Charter for Researchers, was adopted by the European Commission in 2005.

At a more local level, some universities have dedicated offices or ombudsmen for postdoc affairs, who can help solve non-research-specific problems like conflicts with senior staff or difficulties adapting to a new environment. Others have active branches of groups like the UK National Research Staff Association, EURODOC or the US National Postdoctoral Association. Such groups can help individuals address problems where they arise, and often assist new postdocs with settling in and building a social life.

In addition to preparation for a research career, a postdoctoral position can offer the chance to experience a new culture for a few years, particularly if one moves abroad. The advantages can be both personal and professional, with the opportunity to raise one’s profile and make important contacts internationally going hand in hand with the fun of living somewhere pleasantly exotic.

Indeed, for physicists from small countries, a move is often an essential step towards obtaining a permanent post. This was certainly the case for Arttu Rajantie, a native of Finland who did a postdoc at the University of Cambridge in the UK. “There is a very good group in my field in Helsinki, but one has to go abroad to develop as a researcher,” says Rajantie, who is now a lecturer in theoretical physics at Imperial College, London.

Bumps on the roadThe down side to life as a modern journeyman is that too much mobility can be destabilizing. This is particularly the case for researchers with families, who often face the “two-body problem” of finding employment for both adults. They may also be reluctant or unable to move children to a new city or country. For those who find themselves doing multiple postdocs in the hope of finding something more permanent, these problems are compounded — particularly if the sought-after post is never obtained.

Interestingly, the number of years spent as a postdoc varies significantly between fields. A survey by the Institute of Physics in 2000 found that nearly a third of astronomers, astrophysicists and particle physicists spent more than seven years in non-permanent positions. For physicists in other sub-disciplines the figure was just 15%.

The stark truth is that in most cases a postdoc is not a ticket to a permanent academic job. The Institute’s poll found that although three out of five physics postdocs wanted a permanent faculty position, only one in five had secured such a post 5–10 years later. A similar fraction were still stuck in postdoc positions.

“Keep in mind that a postdoc is supposed to be a fixed-term position and is unlikely to lead to a permanent position, no matter what the job ad says,” cautions Damian Audley, a research associate working on cryogenic detectors in Cambridge University’s astrophysics group. “Think about how it fits into your career goals and what your next step will be.”

The employment picture from the poll was not all gloomy. Of those surveyed, 91% had found jobs that used their research skills, even though more than half were no longer working in higher education. Common employers for former physics postdocs included IT and financial firms, as well as government and industrial research labs. The survey also indicated that industry placed a high value on the presentation, self motivation and problem- solving skills that postdocs developed.

As for salaries, postdoc pay is relatively poor. The Sigma Xi study found that while a postdoc in their early 30s (the median age for postdocs) could expect a median salary of $38,000, the comparable figure for a young thirty-something with only a bachelor’s degree was $45,000. With grim humour, the authors noted that after factoring in their median 51 hour working week, a postdoc’s hourly wage is only slightly better than that of a janitor or caretaker at Harvard University.

However, the study included responses from postdocs in the life sciences as well as physics, and median salaries for physicists tend to be higher. Postdocs working in government labs can also expect a bigger paycheck; salaries for postdocs at the Los Alamos National Laboratory, for example, currently start at $67,400. Surprisingly, the Sigma Xi study did not find any relationship between salaries and postdoc satisfaction: better-paid postdocs were no happier than their poorer peers, published only marginally more papers per year, and were slightly more likely to report conflicts.

Other directionsPhysics postdocs whose long-term interests lie outside the ivory tower (including the 40% who never seek an academic post) have traditionally had the option of doing a postdoc in industry. That avenue is more limited today. Dresselhaus, who has been involved in numerous studies of scientists’ career paths, cited the demise of Bell Labs (see page 39, print version only) as both a cause and an indication of reduced industry opportunities for physicists doing pure research. However, postdocs involving collaborations between industrial and university partners are still possible, and funding bodies are keen to promote such cooperation.

“The research councils are trying to exploit the research that they support such that we create wealth and have an economic impact,” says Alan Thomas of EPSRC. Thomas, whose job is to build business-focused skills for researchers, notes that all EPSRC-funded postdoctoral fellowships can be done in partnership with industry. “People’s familiarity with the industrial environment and the drivers there will stand them in good stead in the future,” he says.

Whether in industry or academia, life as a postdoc has its advantages. “The opportunity to be paid for thinking about the early universe and continue to do this for a real career was too good to miss,” says Steven Gratton, a postdoc in theoretical cosmology at Cambridge University. “I’ve had the chance to interact and collaborate with some really inspiring people [and] I’ve learned all sorts of skills, including computer programming and giving presentations.” Despite the stiff competition, Rajantie thinks that if you are serious about doing research, a postdoc is essential. “You should go for it…it is worth trying, and in any case you will gain some valuable experience.”